Most TV crime dramas are whodunits. Columbo famously reversed things by starting with the murder, and making it a "How'd he get him?" Mindhunter, in contrast to both those approaches, is all about motive. It's a "Whydunit."

Decades of crime entertainment - ahem, CSI - have turned all of us into armchair sleuths, and the majority of movies and shows know that. Mindhunter is rewarding as hell to watch for entirely the opposite reason.